(Almost?) all other other major vendors at the time used it heavily too: Microsoft Office until 2011, FileMaker until 2010.
If Apple released the OS a year earlier, but without any available third-party software (waiting for almost-rewrites to happen), would they really have been better off? At this time they were on life support and would have had difficulty convincing third-party vendors to invest heavily in their platform, or to convince users to adopt it without any major applications available.
In either case, Adobe's sway clearly declined over the years, as Apple cancelled the 64bit version of Carbon while Adobe was still heavily built around it, forcing Adobe to switch (and an awkward year or two when the Mac, but not Windows, versions were stuck with 32bit memory limitations)
